Postnatal health and welfare of offspring conceived in vitro: a case for epidemiological studies

In vitro fertilization (IVF) has established itself as an important technique in human assisted reproduction and in livestock improvement. In both humans and livestock the possible long-term effects on health and welfare of offspring born after IVF and in vitro culture to the blastocyst stage are still largely unknown. Epidemiological studies in humans, using data collected for individuals born after normal (i.e. non-assisted) pregnancies, have provided evidence for associations between prenatal life events and adult-life disease. Due to the relatively short time that elapsed since the first IVF baby was born, comparable studies for IVF offspring are not yet possible. However, animal experiments and epidemiological studies with the available data from the livestock industry (mainly dairy cattle) may contribute to a better understanding of the risks involved.